Skip to content
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed
  1. Home
  2. /
  3. Compare
  4. /
  5. ChatGPT-4o (March 2025)vsClaude Opus 5.5
Updated Sep 2026

ChatGPT-4o (March 2025)vsClaude Opus 5.5

Claude Opus 5.5 is cheaper than ChatGPT-4o (March 2025) at $4/M vs $5/M input tokens.

ChatGPT-4o (March 2025) and Claude Opus 5.5 compared across 17 shared prompts
SpecChatGPT-4o (March 2025)Claude Opus 5.5
Input price$5/M tokens$4/M tokens
Output price$15/M tokens$20/M tokens
Context window128K tokens1.0M tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedMar 2025Sep 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 17 prompts both answered. Formatting stripped, words untouched.

Simple 7-Ingredient Recipe

Create a simple recipe for a delicious dish (sweet or savory) using only 7 common pantry ingredients. Include a creative name for the dish…

ChatGPT-4o (March 2025)265 words
Recipe Name: Maple Cinnamon Toast Bites Description: A quick and delicious sweet treat made with pantry staples! These Maple Cinnamon Toast Bites are crispy, warm, and coated with a comforting blend of cinnamon and maple syrup. Perfect for a cozy snack or a fun breakfast twist.
Read the full answer
Claude Opus 5.5300 words
Midnight Silk Noodles Creamy, tangy peanut noodles with a gentle kick, ready faster than takeout. Serves: 2 Prep time: 5 minutes Cook time: 10 minutes Total time: 15 minutes The 7 Ingredients 8 oz (225 g) spaghetti (or any long noodle) ¼ cup creamy peanut butter 3 tablespoons soy sauce 1 tablespoon honey (or sugar) 1…
Read the full answer

Debug This Architecture

Here's the architecture for a real-time collaborative document editor (like Google Docs): **System Overview:** - Frontend: React SPA with…

ChatGPT-4o (March 2025)876 words
This architecture for a real-time collaborative document editor is a solid starting point, but it contains several potential failure modes, race conditions, and scaling bottlenecks. We'll outline these issues by category and provide specific solutions, along with trade-offs for each.
Read the full answer
Claude Opus 5.52,280 words
Architecture Review: Real-Time Collaborative Editor The most serious problems cluster in three areas: the sync model (client-clock LWW), cross-server propagation (per-server WebSockets with DB polling), and the CDN/auth layer, which can leak data between users. Issues are grouped by area below.
Read the full answer

Historical Counterfactual Analysis

If the transistor had been invented in 1920 instead of 1947, trace the likely technological, economic, and geopolitical implications through…

ChatGPT-4o (March 2025)1,096 words
If the transistor had been invented in 1920 rather than 1947, it would have profoundly altered the course of 20th-century history. The transistor—a small semiconductor device capable of amplifying and switching electronic signals—replaced bulky, fragile vacuum tubes and enabled the miniaturization and mass production…
Read the full answer
Claude Opus 5.53,435 words
The Transistor in 1920: A Counterfactual Through 1980 First, a Reality Check on the Premise A transistor "invented" in 1920 would not have changed the world in 1920. The actual 1947 transistor rested on three foundations that did not exist yet: Quantum theory of solids.
Read the full answer

Ethical Dilemma with Stakeholders

You're the CEO of a pharmaceutical company. Your best-selling drug ($2B annual revenue, used by 4 million patients for chronic pain) has…

ChatGPT-4o (March 2025)958 words
This is a high-stakes ethical, legal, and business crisis requiring immediate, strategic, and transparent leadership. As CEO, my ultimate responsibilities are to protect patients, preserve trust, comply with legal and regulatory obligations, and ensure long-term viability of the company—even if it causes short-term…
Read the full answer
Claude Opus 5.51,853 words
The Next 48 Hours: CEO Action Plan The Core Decision We disclose. The question is how to do it well, not whether. Before the schedule, here are the three facts that drive every decision below. 1. The harm is concrete.
Read the full answer

Explain Like I'm a Specific Expert

Explain how a large language model (like GPT or Claude) learns and generates text to each of these three audiences: 1. **An experienced…

ChatGPT-4o (March 2025)704 words
Certainly! Here's how to explain large language models (LLMs) like GPT or Claude to each of your three audiences, with framing and emphasis tailored to their backgrounds and concerns: The Experienced Software Engineer Think of a large language model as a massively distributed, probabilistic autocomplete engine trained…
Read the full answer
Claude Opus 5.51,442 words
How Large Language Models Work: Three Explanations For the Experienced Software Engineer Think of an LLM as a single, very large pure function: f(tokens[0..n]) → probability distribution over tokens[n+1]. Text is chunked into tokens (roughly word fragments, from a vocabulary of about 100k).
Read the full answer

Startup Pitch Teardown

Here's a pitch deck summary for a startup called "MindMeld AI": **Slide 1 - Vision:** "We're building the future of human-AI collaboration.…

ChatGPT-4o (March 2025)493 words
Here are the three weakest claims in the MindMeld AI pitch deck, along with explanations of why they are weak and suggestions for improving them: 🟠 Weak Claim 1: Slide 1 – Vision Quote: “MindMeld AI reads your brainwaves to predict what you want to type before you think it.”
Read the full answer
Claude Opus 5.5936 words
The 3 Weakest Claims in the MindMeld AI Pitch "Decodes neural patterns into text with 94% accuracy. Works with any language, any device." (Slide 3) Why it's weak: It far exceeds the published state of the art. The best results for thought-to-text come from invasive implants.
Read the full answer
Our Verdict
ChatGPT-4o (March 2025)
ChatGPT-4o (March 2025)
Claude Opus 5.5
Claude Opus 5.5

Not enough votes to call it. On the specs, nothing separates them.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

ChatGPT-4o (March 2025)
Input
$5.00
Output
$15.00
1.3× cheaper
Claude Opus 5.5
Input
$4.00
1.3× cheaper
Output
$20.00

Claude Opus 5.5 wins input (1.3× cheaper)·ChatGPT-4o (March 2025) wins output (1.3× cheaper)

Where to run it

4 hosts

ChatGPT-4o (March 2025)

No hosts listed on OpenRouter.

Claude Opus 5.54 hosts
HostInOutContextUptime
Amazon Bedrock$4.00 in·$20.00 out·1M·99.8% upAzure AI Foundry$4.00 in·$20.00 out·1M·100% upAnthropic$4.00 in·$20.00 out·1M·100% upGoogle Vertex AI$4.00 in·$20.00 out·1M·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

ChatGPT-4o (March 2025) is developed by OpenAI while Claude Opus 5.5 is developed by Anthropic. ChatGPT-4o (March 2025) has a 128K token context window vs Claude Opus 5.5's 1.0M. You can compare their actual outputs across 17 challenges on Rival to see how they differ in practice.

It depends on your use case. ChatGPT-4o (March 2025) and Claude Opus 5.5 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 17 challenges so you can judge which fits your needs best.

ChatGPT-4o (March 2025) costs $5/M input tokens and Claude Opus 5.5 costs $4/M input tokens. Claude Opus 5.5 is $1.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

This page shows a side-by-side comparison of ChatGPT-4o (March 2025) and Claude Opus 5.5 across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

Keep exploring

More comparisons

Against the newest arrivals

ChatGPT-4o (March 2025) logoSolar Mini 4 logo
ChatGPT-4o (March 2025) vs Solar Mini 4Landed Sep 2026
Claude Opus 5.5 logoQwen3.8 Max Prime logo
Claude Opus 5.5 vs Qwen3.8 Max PrimeLanded Sep 2026
ChatGPT-4o (March 2025) logoGLM 5.3 Prime logo
ChatGPT-4o (March 2025) vs GLM 5.3 PrimeLanded Sep 2026
Claude Opus 5.5 logoQwen3.8 Omni Flash logo
Claude Opus 5.5 vs Qwen3.8 Omni FlashLanded Sep 2026
ChatGPT-4o (March 2025) logoCommand A+ logo
ChatGPT-4o (March 2025) vs Command A+Landed Sep 2026
Claude Opus 5.5 logoGPT-6 Luna Pro logo
Claude Opus 5.5 vs GPT-6 Luna ProLanded Sep 2026
ChatGPT-4o (March 2025) logoGPT-6 Sol Pro logo
ChatGPT-4o (March 2025) vs GPT-6 Sol ProLanded Sep 2026
Claude Opus 5.5 logoGPT-6 Luna logo
Claude Opus 5.5 vs GPT-6 LunaLanded Sep 2026

Same lab, same size, long tail

ChatGPT-4o (March 2025) logoGPT-6 Luna Pro logo
ChatGPT-4o (March 2025) vs GPT-6 Luna ProSame lab
ChatGPT-4o (March 2025) logoGPT-6 Luna logo
ChatGPT-4o (March 2025) vs GPT-6 LunaSame lab
Claude Opus 5.5 logoClaude Opus 4.6 logo
Claude Opus 5.5 vs Claude Opus 4.6Same lab
Claude Opus 5.5 logoClaude Fable 5.1 logo
Claude Opus 5.5 vs Claude Fable 5.1Same lab
Claude Opus 5.5 logoGLM 4.5 logo
Claude Opus 5.5 vs GLM 4.5Same size
Claude Opus 5.5 logoGLM 4.5 Air logo
Claude Opus 5.5 vs GLM 4.5 AirSame size
Claude Opus 5.5 logoGLM 4.6 logo
Claude Opus 5.5 vs GLM 4.6New provider
Claude Opus 5.5 logoGLM 4.7 logo
Claude Opus 5.5 vs GLM 4.7Same size

Model pages

ChatGPT-4o (March 2025) logo
ChatGPT-4o (March 2025)33 outputs, specs and price
Claude Opus 5.5 logo
Claude Opus 5.519 outputs, specs and price
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed